Synchronized clock system and secondary clock therefor



J. W. BRYCE Oct. 3, 1933.

SYNCHRONIZED CLOCK SYSTEM AND SECONDARY CLOCK THEREFOR Filed May 2. 1929 S-vwentoz 71'. 5

Patented Oct. 3, 1933 PATENT OFFICE SYNCHBONIZED CLOCK SYSTEM AND SEC- ONDARY CLOCK THEREFOR James W. Bryce, Bloomfield, N. 1., assignor, by.

means assignments, to International Business Machines Corporation, New York, N. Y., a corporation of New York Application May 2, 1929. Serial No. 359,751

- 15 Claims.

This invention relates to improvements in synchronized clock systems and in secondary clocks for use in such systems and more particularly the present invention is directed to improvements in the system and secondary clock which is disclosed and claimed in the patent of James W. Bryce and Charles H. Getz, No. 1,774,330, dated December 17, 1929.

One object of the present invention resides in the provision of an improved synchronized clock system including a master clock and one or more secondary clocks wherein a single circuit is employed between the master clock and secondary clocks, both for the transmitting of the actuating impulses to the secondary clocks and for synchronizing the secondary clocks with the master clocks and in which an improved and simplified secondary clock construction is employed for selectively determining whether the secondary clock shall advance or remain at rest.

A further object of the present invention resides in the provision of a secondary clock provided with a multiple winding, the effectiveness of the turns of which are controlled by the chronological condition of the secondary clock.

A further object of the present invention resides in the provision of a synchronized clock system in which the releasing impulse or impulses are sent at a voltage which is diiierent from the voltage of the normal impulses and in which provision is made in the secondary clock for selecting the impulses for efiective or ineffective action to actuate the clock in accordance with the interrelation of the windings of the impulse magnet of the secondary clock. The interrelation of such windings is controlled in accordance with the chronological condition of each individual secondary clock.

A further object of the present invention resides in the provision of an improved secondary clock of the impulse type for use in synchronized clock systems in which the secondary clock is provided with a differentially wound impulse magnet, with the diflerential windings of such magnet so arranged that they control the action or non-action of the impulse magnet in accordance with the voltage characteristics of impulses which are received by the secondary clock.

Further and other objects will be hereinafter set forth in the accompanying specification and claims and shown in the drawing which by way of illustration shows what I now consider to be a preferred embodiment of the invention.

In the drawing:

Fig. 1 is a diagram of a complete clock system irliclikisding a master clock and several secondary 0 oc Fig. 2 is an enlarged detail view of the salient features of a secondary clock incorporating the present improvements.

The diagram shows a preferred embodiment of the invention. In the diagram the master clock is shown at the left and it is of any conventional type provided with the usual time train adapted to drive the minute arbor 10 which makes one revolution per hour. 11 is the usual verge or escapement mechanism of the clock. 12 and 15 are cams associated with the minute arbor and adapted to control the opening and closing of contacts 14 and 16. There is also provided a 7 kept in the position shown. In'order to transmit the normal impulses to the secondaries over line 37, the action is as follows: Current flows from ground G through the battery B, through switch 32, wire 33, through the minute impulse contacts 17 which close once a minute, then through relay coil 34 and back to ground G. Energization of 34 closes relay contacts 35 once a minute and transmits low voltage impulses to line 37 in the following manner: Starting from ground G there is a circuit established through a part of the battery B thereby providing a relatively low voltage supply, thence via wire 42 to contacts 43 now closed, via 45 to 35 and thence to line 37 through the various secondary clocks and back to ground G. It will be understood that contacts 35 close once per minute which permit the low voltage impulses to flow out from 45 over the line 37. It will be understood that the low voltage supply herein illustrated wherein a part of the battery 13 is employed to provide for such low voltage supply shows only one way of obtaining such low voltage supply for the current impulses. 0bviously other kinds of current supply could be provided in which current can be supplied at either one of two diiferent voltages.

At a determined time or times in the hour, for example, once per hour as determined by the cronological condition of the master clock, contacts 16 are closed for say thirty seconds or longer if desired and such period of closure may precede a 59th minute as indicated by the master clock hands. Closure of these contacts 16 permit current to flow to 19 which close in rapid succession to energize 34 in rapid succession and to thereby send out a series of more rapidly recurring impulses over the line 37. The rapid impulses are also sent out at the low voltage as will be readily understood and such impulses are for accelerating and stepping ahead any slow clocks.

At exactly the 59th minute or at more often intervals if desired, provided the balance of the system is so arranged contacts 14 close. The effect of the closure of these contacts is to energize coil 40, thus opening contacts 43 and closing contacts 430. This action puts the full potential of the battery or other source (instead of the relatively decreased potential as heretofore upon line 45) so that at least one and preferably several high voltage impulses are sent out over line 37. This high voltage impulse or the plurality of high voltage impulses again act to step 011 secondary clocks whose action has been suspended in the manner hereinafter explained.

Switch 32 can be thrown to mid-position to stop the secondary clocks and if it is desired to rapidly step the clocks ahead at any time under manual control such switch 32 can be thrown to connect with the upper pole which extends to the contacts 19.

In the diagram three secondary clocks are shown connected in multiple or parallel with each other and connecting with line 37 and also with ground G. There is thus a single circuit between the master clock and the various secondaries, one side comprising line 37 and the other side comprising the ground G. It will, of course, be obvious that a full metallic return could be provided in lieu of the groundreturn. There is also only a single wire or circuit extending into and out of each secondary clock.

The construction of the secondaries will now be described.

Each secondary clock includes an impulse magnet generally designated 21 and having a multiple winding for example, in two parts as designated 21c and 21d. 21a is the usual spring pawl structure which cooperates with the ratchet wheel 22 of the clock which is mounted upon the arbor 20 which rotates once an hour. The arbor 20 also carries a contact controlling cam 50. The cooperating contacts 51 are disposed in circuit in such a manner that when such contacts are closed, magnet winding section 21d will be short circuited by the contacts and when such contacts 51 are open, such winding 21d will be in series with 21c. Winding 21d contains less turns than 210 i. e. the windings are differential windings, and the sections are so wound and connected as to oppose or buck each other when both windings are energized.

When low voltage impulses are being received by a secondary clock whose winding 21d is short circuited, the winding 210 is sufliciently energized to elfectively operate the pawl devices 21a and cause an impulse advance of the clock.

When the low voltage impulses are received by a secondary clock whose winding 21d is in circuit (1. e. not short circuited) the voltage of the low voltage impulses will be insufficient to cause effective attraction of the armature of the pawl device 21a. Under these latter conditions, that is with 21d in circuit, efiective operation of 21a can only be secured when higher voltage impulses are received.

The action may be explained more in detail by assuming the following dimensions and constants of an illustrated case. Assume winding 21d to be one of 2000 turns and having a resistance of 500 ohms and winding 21c to be a winding of 4000 turns having a resistance of 1000 ohms and that it requires 40 ampere turns to cause suflicient magnetization of the core to effectively operate 21a. First consider a secondary clock in which winding 21d is short circuited and low voltage impulses of say 10 volts being received. The current flowing through 210 will be 10 divided by 1000, that is one one-hundredths amperes which multiplied by 4000 equals 40 ampere turns which is suflicient to cause effective operation of 21a.

Now assume the same conditions except that 21d is in circuit (1. e., not short circuited). The two windings 21c and 21d are now in series and have a total resistance of 1500 ohms. The current flowing will therefore be 10 divided by 1500 i. e. .006 amperes. The ampere turns of 21c therefore equals 4000 multiplied by .006 which equals 24. The ampere turns of 21d equals 2000 multiplied by .006 equals 12. In view of the opposition of the coils 21c and 21d the eifective ampere turns equal 24 minus 12 or 12 which is insufficient to cause operation of 21a.

Now assume the same condition as last 'assumed but with voltage impulses of 40 volts potential instead of 10 as heretofore. The current flowing through the two windings in series will be 40 divided by 15, i. e. about .024 amperes. The ampere turns of winding 21c will then be 4000 multiplied by .024, i. e. about 96 and the ampere turns of 21d will be 2000 multiplied by .024 equals 48. The effective ampere turns then will be 96 minus 48 or 48, which is enough to operate 21a.

Accordingly, it will be understood that in the above system, provision is made for sending out from the master clock to the secondary clocks, normal low voltage impulses. Periodically a number of fast impulses also of low voltage will be sent out over the same line 37. These fast impulses will step up any clocks which are slow and the advance of the clocks will continue until contacts 51 open. If clocks are on time the fast impulse would also tend to step ahead the clocks but the opening of contacts 51 would prevent such stepping ahead the clocks. With fast clocks 51 would open and stop the clocks. Opening of 51 occurs at a time when the secondary clock hands indicate a 59 minute condition. At such time, irrespective of additional normal or fast impulses being received by any secondary clocks such impulses will be ineifective to advance any clock. However, when the master clock has reached a time condition in which it indicates 59 minutes, such master clock will send out at least one and possibly more impulses of higher voltage. When such impulse of higher voltage is received by any secondary clock, such secondary clock will again be stepped off and contacts 51 will reclose whereupon each secondary clock will again be in such condition that it is capable of being stepped ahead by the following low voltage impulses.

It will be appreciated that the stepping up and release of the secondary clocks can be eifected more frequently than once an hour by properly arranging the contour of cams 15 and 12 in the master clock and correspondingly arranging the contour of cams 50 in the secondary clocks. However, for purpose of illustration, a once per hour action has been explained.

It will be also understod as heretofore stated,

that the invention is not limited to a battery supply system. Other sources oivariable voltage can be used, for example, a transformer may be employed operating on alternating current with tapped or separate windings to provide variable voltage and a suitable rectifier may be employed to convert the current supply for the secondary clocks from A. C. to D. C. This and other modifications are all within the scope of the present invention and are in the scope of the appended claims.

What I claim is:

1. In a synchronized clock system of the type wherein a single line is employed between the master clock and in secondary clocks for transmitting actuating impulses to the secondary clocks from the master clock and for eflecting synchronization between the secondary clocks and the master clock and including in combination in the secondary clocks impulse magnet means provided with multiple windings adapted for conjoint energization or partial energization, and means in the secondary clocks for controlling the conjoint or partial energization of said windings solely in accordance with the chronological condition of the secondary clocks.

2. A secondary clock for use in a one wire type of synchonized clock system in which impulses of varying voltage are sent out from the master clock to the secondaries over a single line circuit, comprising an impulse magnet having mutiple windings, means controlled by the clock for short circuiting one winding under certain chronological conditions of the clock whereby the magnet is inefiective when not short circuited under impulses of a certain voltage and effective under impulses of that voltage when the one winding is short circuited.

3. A secondary clock for use in a synchronized impulse system, said clock comprising an impulse magnet having differential windings, means controlled by solely and only the chronological condition of the clock for causing said windings to be connected to oppose each other under certain chronological conditions of the clock, and means controlled also solely and only by the chronological condition of the clock for causing the received impulses to flow through one of the windings only under certain chronological conditions of the clock.

4. A secondary clock adapted for use in an impulse and synchronized clock system wherein a single line connection extends into each secondary clock and impulse magnet connected to said single line having multiple windings through which current impulses are received over said single line connection flow, means controlled by the chronological condition of the secondary clock for causing impulses flowing to the impulse magnet from said single line to selectively flow in series through both of the windings or only to flow through one of the windings.

5. A synchronized clock system including a master clock, one or more secondary clocks, a single line circuit connecting the master clock with all of the secondaries, and means in the master clock for sending out normal impulses of one voltage, fast impulses of a given voltage and at least one impulse of a higher voltage and comprising in combination a secondary clock including an impulse magnet and means for selectively controlling the effectiveness of operation of said magnet under received impulses, said .pulse magnet is supressed when low voltage immeans comprising multiple windings for said magnet and means for connecting said windings under control 0! the chronological condition 0! the secondary clock so that under certain time conditions both windings receive the impulses and so that under other time conditions one winding only receives the impulses and the other winding does not receive the impulses whereby the effectiveness of action of the impulses are received and made again effective when high voltage impulses are received.

6. A secondary clock having a single line feeding impulses in and out of the same, and having an impulse magnet provided with multiple windings, means controlled by the chronological condition of said clock for at certain times connecting both windings in series with the single line circuit whereby the action of the magnet will be ineiiective when low voltage impulses are received and whereby the action of the magnet will be eileetive when high voltage impulses are received.

7. The invention set forth in claim 6 in which means are provided for placing one portion of the multiple winding in series with the line and for cutting another portion of the multiple winding out of circuit with the line, said means being controlled by the chronological condition of the secondary clock so that the impulse magnet will be efiective to actuate the clock when impulses of one voltage are received and also eflective to operate the clock when impulses of a different voltage are received.

' 8. An impulse type 01' secondary clock for use in a synchronized clock system in which control of the secondaries for synchronization is afforded by the control of the voltage characteristics of impulses which flow to the clock and including in combination an impulse magnet in the secondary clock having diilferential windings, and means controlled by the chronological condition of the clock for placing said windings in bucking relation to each other so that received low voltage impulses will be ineffective to operate the clock and so that received high voltage impulses will be effective to operate the clock.

9. An impulse type of secondary clock for use in a synchronized clock system in which control of the secondaries for synchronization is ailorded by the control of the voltage characteristics of impulses which flow to the clock and including in combination an impulse magnet in the secondary clock having diflerential windings, said windings being at certain times as controlled by the chronological condition or the secondary clock disposed in bucking relation to one another so that received low voltage impulses will be ineffective to operate the clock and means also controlled solely by the chronological condition of the clock for removing one winding from bucking relation to the other winding so that received low voltage impulses will still be efiective to operate the clock.

10. An impulse type of secondary clock suitable for single circuit operation and including a single impulse circuit extending to and from the clock, an impulse magnet having difierential windings arranged to buck one another when connected in series in the single impulse cir- 146 cult, and means operating under the chronological control of the secondary clock itself for selectively, under certain chronological conditions of the clock itself, placing said windings in series bucking relation for flow of the same current 1111- 150 pulses serially through both of the diflerential bucking windings so that impulse advance or the clock may be suppressed under such chronological conditions with certain current impulses and permitted with other current impulses.

11. An impulse type of secondary clock suitable for single circuit impulse operation including an impulse magnet having diflerential windings arranged to buck one another when connected in series in the single impulse circuit and upon flow of the -same impulse serially through both bucking diflerential windings, and means controlled solely by the chronological condition of the secondary clock for rendering one winding ineffective to buck the other winding.

12. An impulse type of secondary clock suitable for single circuit operation and including an impulse magnet having diflerential windings disposed serially in bucking relation to one another in the single circuit for serial flow of impulses through both windings, and switching means controlled by the chronological condition of the secondary clock itself for rendering one winding inefl'ective to buck the other winding.

13. The invention set forth in claim 12 in which the switching means is connected to always maintain one 01 the windings in the single circuit irrespective of whether the other winding is in bucking relation or out of bucking relation.

14. An impulse type 01 secondary clock suitable for single circuit operation and synchronization control, including an impulse magnet having multiple windings serially connected together and difierential in character as regards their relative number of turns and also wound to buck each other upon the flow of current impulses through both windings, with switching means controlled by the chronological condition of the secondary clock itself for rendering one winding eflective or ineffective to buck the other winding, said multiple differential serially connected and bucking windings by means of the relative number of turns of one winding with respect to the other and by the relation of the switching means cooperating to effect suppression oi impulse advance of the clock upon receipt of one character of impulses with one winding in bucking relation to the other and to permit impulse advance of the clock with the bucking relation of the windings maintained but with a different character of impulses flowing through both of the windings, and also cooperating to provide for an impulse advance or the clock by received impulses ot either character when the switching means has rendered one winding ineflective to buck the other.

15. An impulse type or secondary clock suitable for single circuit operation and synchronization including a single supply circuit extending into the clock over which flow the normal and fast impulses which are or relatively low voltage and at least one synchronization impulse of relatively high voltage, said clock also including an impulse magnet with two windings having a relatively diiferent number of turns and serially connected together and also connected in series relation with said supply circuit, said pair of windings being also arranged in bucking relation to one another, means controlled by the chronological condition oi the secondary clock itself for rendering the windings effective to differentially buck one another so that received impulses of low voltage upon flowing through both diflerential windings will be inefiective to advance the clock but so that a received synchronizing impulse of higher voltage upon flowing through both windings will be effective to advance the clock irrespective of the bucking relation 01' the said windings, the aforesaid means controlled by the chronological condition of the secondary clock being also adapted to render one winding ineilective to buck the other winding so that a received impulse of either a high or low voltage will be effective to advance the clock.

JAMES W. BRYCE. 

